﻿using System;
using System.Text;

namespace XiaoSe
{
    public static class StringEx
    {
        public static string CutString(this string value, int length)
        {
            return value.Length <= length ? value : value.Substring(0, length);
        }

        public static string CreateRandomStr(int length)
        {
            StringBuilder sCode = new StringBuilder(length);
            var r = new Random();
            char[] cNumAndLetter = { '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z' };
            for (var i = 0; i < length; i++)
            {
                int iRandom = r.Next(0, cNumAndLetter.Length);
                sCode.Append(cNumAndLetter[iRandom]);
            }
            return sCode.ToString();
        }
    }
}
